Enhanced inertial focusing of microparticles and cells by integrating trapezoidal microchambers in spiral microfluidic channels

Ala'aldeen Al-Halhouli, Ahmed Albagdady, Wisam Al-Faqheri, Jonathan Kottmeier, Sven Meinen, Lasse Jannis Frey, Rainer Krull, Andreas Dietzel

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fractionation devices by embedding microchambers along the last turn of a spiral is reported. Microchambers with different shapes and sizes were tested at Reynolds numbers between 15.7 and 156.6 (100–1000 μL min−1) to observe focusing of 2, 5 and 10 μm fluorescent microparticles. This paper also discusses the fabrication process of the microfluidic chips with femtosecond laser ablation on glass wafers, as well as a particle imaging velocimetry (μPIV) study of microparticle trajectories inside a microchamber. It could be demonstrated with an improved final design with inclined microchamber side walls, that the 2 μm particle equilibrium position is shifted towards the inner wall by ∼27 μm and the focusing line's width is reduced by ∼18 μm. Finally, Saccharomyces cerevisiae yeast cells were tested in the final chip and a cell focusing efficiency of 99.1% is achieved.
Original languageEnglish
Pages (from-to)19197–19204
Number of pages8
JournalRSC Advances
Issue number9
Publication statusPublished - 18 Jun 2019
Externally publishedYes

Bibliographical note

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes


This research is financially supported by the German Academic Exchange Service (DAAD) under the project entitled “Inertial focusing for continuous nanoparticles separation in femtosecond laser 3D micromachined curved channels”. Special thanks to Nanolab engineers, especially Zaid Doofesh for assisting in chips fabrication and Loiy Alghussain for his support in data analysis. Also, special thanks to Adnan Al-Lahham and Sundos Asfour for assisting in early cells experiments. Jonathan Kottmeier is funded by the DFG Project SPP2045 “MehrDimPart”. Lasse Frey and Sven Meinen gratefully acknowledge financial support from the German Research Foundation (DFG) within the project “Development of micro-reactors for biopharmaceutical applications” (DI 1934/9-1, KR 1897/5-1).


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